The present invention relates to a device for tracking the apparent motion of the sun across the sky and concentrating the radiant energy received from the sun on a fixed target area. More particularly, the invention relates to what may be described as a "ganged heliostat", that is, an array of heliostats controlled by a single mechanism such that each heliostat redirects rays of the sun toward a common fixed target area and thereby concentrates the rays of the sun received over a large area to a smaller target area.
The efficient utilization of solar energy is a problem receiving widespread attention in industry today. One potential solution is in the development of solar cells by the semi-conductor and allied industries for converting the radient energy of the sun into electrical power. Most, if not all, conventional solar cells are quite expensive and in order to be economically viable, they must have a high efficiency. One method of improving the efficiency of solar cells is by concentrating incident sunlight received over a large area onto the cells. Another method is to have the cell or associated equipment for the cell track the apparent motion of the sun across the sky so as to maximize the amount of incident sunlight received per cell unit area over the course of a day.
While various devices are known in the art for concentrating sunlight on a particular solar device and/or for tracking the apparent motion of the sun, such mechanisms have various inherent disadvantages such as being complex, expensive, difficult to maintain and prone to gradually work out of proper adjustment for maximum utility. Examples of these known devices are those disclosed in U.S. Pat. Nos. 913,051 to Pope, 1,219,372 to Butterfield, 1,938,003 to Arthuys et al, 1,876,428 to Arthuys et al, 2,022,144 to Nicholson, 2,135,997 to Arthuys, 2,712,772 to Trombe, 3,656,844 to Botskor, and 3,951,510 to Lloyd.
It is therefore an object of the present invention to provide a device for tracking the apparent motion of the sun across the sky and for concentrating the rays received therefrom on a fixed target area.
Another object of the present invention is to provide a device which is relatively uncomplicated, requires a minimum amount of maintenance, is relatively inexpensive to manufacture and requires relatively small amounts of energy for operation.
Yet another object of the present invention is to provide a device which is able to be adjusted so to compensate for the changes in the apparent motion of the sun from day to day.
The invention in its broadest aspect comprises a device adapted for tracking the motion of the sun and reflecting and thereby concentrating rays of the sun to a fixed target area which includes at least two members each having a reflective surface and being rotatably mounted in a frame on an axis which passes through the center point of the member, each frame being rotatably mounted in a common support on an axis which passes through the center point of the member and is at a right angle to the axis of the member, a control rod having a longitudinal axis attached to each member such that the axis of the control rod is normal to the reflective surface of the member and passes through the center point of the member, guide frame means in engagement with each control rod, driving means for moving the guide frame such that each member rotates about one axis and is thereby capable of tracking the apparent motion of the sun, and adjusting means for moving the guide frame means such that each member rotates relative to the other axis.
Further objects, advantages, and features of the present invention will become more fully apparent from a detailed consideration of the arrangement and construction of the constituent parts as set forth in the following specification taken together with the accompanying drawing.